(1) Field of the Invention
Motorcycles have a wide of variety of exhaust systems, including headers, exhaust pipes, and mufflers. Multi-cylinder motorcycles typically have exhaust ports on both sides of the motorcycle, wherein the exhaust gas is directed through ports leading to headers. The headers are normally routed to one side of the motorcycle into a single exhaust pipe, or dual exhaust pipes on the larger motorcycles.
An exhaust system contributes to an increase in the efficiency of a reciprocating engine by means of the length of the exhaust pipe(s) connected to the engine. A good resolution of the task of increasing efficiency is to provide for an expansion volume in the exhaust gas line into which the exhaust pipes lead, if the said volume can be made large enough. Exhaust system arrangements have been designed in a variety of ways, quite often, based on increasing the cross-sectional surface area of the exhaust pipes so as to equal or exceed the cross-sectional area of the exhaust ports.
(2) Description of the Related Art, including information disclosed under 37 CFR 1.97 and 1.98.
In U.S. Pat. No. 4,800,719 (Campbell 1989) the inventor has designed an exhaust system for a multiple cylinder motorcycle engine which provides that pipes leading from the exhaust ports of the engine flow into a collection chamber. The collection chamber further has two discharge pipes which terminate with a silencing device at the end of each.
U.S. design Pat. No. D454,320 (Martin, 2002) depicts two curvilinear headers which symmetrically collect exhaust gasses leading from the exhaust ports of a motorcycle engine, further extending and routed to form a closely joined curvilinear pair of exhaust pipes on one side of the motorcycle.
U.S. patent application publication US2002/0083703 (Werth, 2002) presents a manifold arrangement for multi-cylinder motorcycle engines. Essentially the system collects exhaust gasses from all cylinders and funnels into two equal-flow exhaust pipes and ultimately into a joint pipe. The joint pipe subsequently divides into two branches which recombine into a single collector pipe in which a wave impedance device is installed.
U.S. Pat. No. D467,847 (Campbell, 2002) illustrates the design for a motorcycle exhaust system comprising a single exhaust header collecting exhaust gasses leading from all the exhaust ports of the motorcycle, with the single exhaust header subsequently diverging into two flared exhaust pipes and/or mufflers.
U.S. Pat. No. D483,710 (James 2003) shows a design for a motorcycle exhaust system comprising two exhaust headers which collect exhaust gasses leading from the exhaust ports of the motorcycle, and subsequently are bent and converged into two adjacent curvilinear exhaust pipes.
U.S. Pat. No. 7,350,351 (Ueshima, A, 2008) is an exhaust system for a motorcycle wherein the system is designed to provide that the exhaust pipes are arranged suitably so that components are positioned as close as possible to the center of gravity of the motorcycle. Generally, exhaust from the right side exhaust ports of the motorcycle are routed into exhaust pipes on the right side, and similarly for the left side of the motorcycle.